75 



occurrence between Umanak Fiord and Ino-lefield Gulf. He thinks ^^ 

 the southern border of the Paleozoic geosyncline of north Greenland 

 coincides with the present border of the inland ice. If this is true, 

 it means that tlie alaciers floAvino- into Melville Bay probably do not 

 carr}^ Paleozoic limestone fragments. The Agpat formation, as was 

 mentioned previously, does not seem to be a likely source of un- 

 metamorphosed limestone. Consequently one infers that the bergs 

 from Melville Bay probably do not carry man}^ limestone fragments. 



Paleozoic limestone is plentiful along the north coast of Green- 

 land, and limestone also occurs in numerous places in the northern 

 archipelago. According to Smith, ^^ bergs from these tAvo regions 

 form 10 per cent of the bergs of Davis Strait. One can not assume 

 that the rock debris they carry consists entirely of limestone frag- 

 ments, but since the glaciers that produce limestone-bearing bergs, 

 flow over a limestone terrain it is probable that the concentration of 

 rock fragments in the ice overlying such areas w^ould be greater than 

 that in ice overlying a gneiss or granite region. Therefore the lime- 

 stone transported by the bergs from north Greenland and the north- 

 ern archipelago may constitute more than 10 per cent of the rock 

 fragments in the sediments of Davis Strait. Pack ice from limestone 

 regions, and bergs from Disko and Melville Bays presumably con- 

 tribute some limestone to the deposits, but if they do not add enough 

 to account for the large quantit}^ of limestone in the sediments, one 

 must consider the hypothesis that more than 10 per cent of the bergs 

 of Davis Strait have sources other than Disko and Melville Bays. 

 Further study of the problem is needed to solve it satisfactorily. 

 It w^ould be especially advantageous to know the types of rock frag- 

 ments carried by the berg-forming glaciers. 



Comments of Lauge Koch. — The question of the origin of the 

 limestone fragments in the sediments was referred to Dr. Lauge 

 Koch, who has spent many years in Greenland. He kindly replied 

 as follows i^*^ 



Along the west coast of Greenland from Cape Farewell to at least 70° North 

 latitude noncrystalline limestone is entirely absent. The whole of west Green- 

 land as far as Disko Bay is made up of gneisses, granites, etc., with the exception 

 of a small area, near Cape Farewell, of red sandstone (age probably pre- 

 Cambrian) which may here be left out of consideration. I think we know the 

 land from Cape Farewell to Disko Bay so well that we are safe in concluding 

 that noncrystalline limestone does not occur along this whole stretch, nor do 

 the moraines of the inland ice in any place seem to indicate the presence of 

 limestone-bearing formations below\the ice cap. 



From 70° North latitude northward to Cape Alexander (the westernmost 

 point of Greenland) there is not the slightest indication of noncrystalline lime- 

 stone. The moraines of the inland ice are here less well known, but everywhere 

 where they have been examined — I may here speak of my own investigations 

 along practically the whole coast — the moraines contain no sediments. (An old 

 statement about the finding of a block of red sandstone in the vicinity of the 

 inland ice east of Umanak has not been confirmed.) In the interior of the 

 Umanak district crystalline limestone and marble of undoubted pre-Cambrian 

 age occurs in association with granites and gneisses. 



As you no doubt know, Disko Island, parts of the Nugsuak Peninsula and 

 the regions north thereof, including parts of the Svartenhuk Peninsula, are 



18 Op. cit, pp. 66-67. 



1® Loc. cit. 



-"Letter of Mai. 4, 1931. 



